This invention relates generally to electrical power transfer and, more particularly, to electrical power transfer switches.
Many businesses use transfer switches to switch between power sources which supply power to the business. For example, from a public utility source to a private secondary supply. Critical equipment and businesses, such as hospitals, airport radar towers, and high volume data centers are dependent upon transfer switches to provide continuous power. More specifically, in the event that power is lost from a primary source, the transfer switch shifts the load from the primary source to an alternate source in a minimal amount of time to facilitate providing continuous electrical power to such equipment and businesses.
At least one known transfer switch utilizes a xe2x80x9cmake-beforebreakxe2x80x9d switch to transfer the load from the primary source to the alternate source. The make before break switch includes dual main contacts which require dual shafts and a plurality of actuators. Transfer switches including dual main contacts and dual shafts may also include dual solenoids to drive the shafts. In the event one of the solenoids fails, the main contacts may remain in an undesired position thereby preventing the transfer switch from activating to enable the business to switch to an alternate power supply.
In one aspect, a method for manufacturing a transfer switch is provided. The method includes providing a transfer switch including a first shunt contact and a second shunt contact, and operationally coupling a shunt solenoid to the first shunt contact and the second shunt contact such that when the solenoid is electrically activated the first shunt contact electrically couples a first source to a load and the second shunt contact electrically couples a second source to the load in a first pre-determined amount of time.
In another aspect, an apparatus for transferring power from a first source to a second source is provided. The apparatus includes a first shunt contact, a second shunt contact, and a shunt solenoid operationally coupled to the first shunt contact and the second shunt contact such that when the shunt solenoid is electrically activated the first shunt contact electrically couples a first source to a load and the second shunt contact electrically couples a second source to the load in a first pre-determined amount of time.